A number of diseases have been identified that may involve transient vascular obstruction secondary to vascular compression resulting in symptoms such as pain in the affected area. For example, chronic exertional compartment syndrome, also known as exercise-induced compartment syndrome, is a disease that generally impacts athletes and can be debilitating. It is caused by reversible ischemia in an affected compartment (i.e., an anatomical space bounded by fascia, bone, etc.) resulting from vascular compression during exertion of muscle(s) in the compartment. Other diseases associated with transient vascular obstruction secondary to vascular compression may also be presented in patients such as, for example, popliteal artery entrapment syndrome.
In the case of exertional compartment syndrome, the patient may feel pain, for example in the calf, which increasingly worsens with exercise. Exertional compartment syndrome is severely painful and may affect high level athletes. The pain typically centers in the calf muscles and progressively worsens with higher levels of activity. The pain is sometimes described by patients as increasing pain and pressure under the skin. The symptoms can seem to the patient to get progressively worse but, in the case of advanced athletes, they may continue to train and exercise to meet goals.
It is believed that the symptoms of pain and tightness are the result of pressure that builds up within one or more muscle compartments of a patient, typically in a limb such as the leg or arm and most typically in the leg. Muscles are surrounded by tight tissue known as fascia, and in normal use the fascia has sufficient space for allowing muscles to function properly. However, in the case of athletes or other exertional use, as activity increases, so may blood flow increase to the muscle. Muscle size increases, but if the fascia is too constrictive, blood flow adjacent to the constricted muscle can be interrupted. Lack of blood flow may lead to ischemia and associated pain.
Previous methods for diagnosis of exertional compartment syndrome may be imprecise and ineffective for determining the location responsible for the interruption in blood flow, thus making treatment of the syndrome more difficult. For example, the symptoms of exertional compartment syndrome may only be present during exertion of one or more muscles in the patient, and any examination of the affected muscle(s) or compartment(s) during exertion may currently be impractical. Accordingly, previous methods for diagnosis of exertional compartment syndrome may include the patient exercising until symptoms develop. Once symptoms have developed, the exercise may be stopped and inter-compartment pressures of the affected area of the patient may be measured (e.g., by an insertable pressure transducer or the like).
However, upon termination of the exercise the potential causes of the symptoms (e.g., increased muscle size, increased blood flow, etc.) may also be terminated such that the symptoms of exertional compartment syndrome may begin to be reduced or alleviated at the termination of the exertion. Thus, upon termination of the exercise, the symptoms may become difficult to detect and/or fleeting. Furthermore, while detection of elevated pressures in compartments of the patient may be indicative of exertional compartment syndrome, increased compartment pressures alone may not be sufficient to identify the location of the interruption of blood flow that is a root cause of the elevated compartment pressures.